Process of obtaining substantially pure nitrogen from the air.



G.BLAGBURN. PROCESS OF OBTAINING SUBSTANTIALLY PURE NITROGEN FROM THE AIR,

' APPLXOATION I'ILED N'OV. 2'7 1907.

Patented Aug. 27, 1912.

[N VENTOR,

A TTORNE Y.

'- Nitrogen. from the Air, of which the following. is a specification. I

' ,from the stream of air sup lied for its comis a diagrammatic sectional view of'the ap-' and width, in order to expose of a charging passage 2 which can be 'bottom 4: of the combustion chamber 1- slopes fur initially, or, if desired, suitable fuel can UNITED sTATEs PATENT OFFICE.

CHARLES BLAGBURN, or AN'I'IDCH, cnmronnm, ,IASSIGNOR To HIMSELF, TRUSTEE.

success or OBTAINING SUBSTANTIALLY PURE NI ROGEN FROM THE AIR.

Application 11166 November 2 To all whom it may concern."

Be it known that I, CHARLES BLAGBURN, a subject of the King of Great Britain, residing at Antioch, in the countyof Contra Costav and State of California, have invented new and useful Improvements in Processes of Obtaining Substantially Pure The object of the present invention is to provide a cheap process of obtaining from the'air practically pure nitrogen. I

The problem ofobtaining nitrogen from the air at a low cost has become in recent times extremely important; first, on account of the greatly increased demand for-nitrate fertilizers to reenrich poor or exhausted. soils; second, on account of the extensive and increasingluse of cyanids in mining an the arts; and, third, on account of the use of nitrogen. gas as a preservative medium for preserving edibles and other perishable articles in air-tight receptacles. p

I have discovered a process, by means of which sulfur may be so burned on a commercial scale as to remove all of .the oxygen bustion, thus solving the nitrogen problem, since this process, on account of the cheapness of sulfur, enables the nitrogen to be obtained'at quite a low cost.

The process herein claimed generically 296,160, filed J anuary, 16, 1906.

In the accompanying drawing, Figure 1 paratus for carrying'out my improved process; Fig.3. is a longitudinal section of the furnace; Fig. 3 is a transverse sectionthereof. 1 indicates a combustion chamber, which is very shallow in proportion to its length a large surface of sulfur to the air of combustion. To said combustion chamber sulfur is fed by means closed when desired-by means of a suitable cover 3. Beneath said combustion chamber is a firebox 50, having a grate 51 and a flue 52, in which a fire can be kindled to heat the sulbe burned'during the process, although .I havenot found this to be necessary! slightly, (the slope being exagvery from front. to rear,

gerated in the drawing) Specification of Letters Patent.

7, 1907. Serial to. 404,120.

ber, to pass necessary to supply er {realize that Patented Aug. 27-, 1912.

to insure the melted sulfur flowing over the entire surface of said bottom. In said combustion chamber and extending across its entire Width is a heating chamber 5, which has a bottom 6, which thus forms the top of the combustion chamber. It slopes downuard fro n a point near the charging ent of the combustion chamber to the outlet 7 thereof. Into said heating chamber air is drawn by suction, as hereinafter described, through a pipe 8, and impinges upon-the sloping bottom thereof. The air in this heating chamber, the combustion of sulfur in the'chamber be neath, emerges from the heating chamber throng downwardly extending pipes 9, by which means it is fed to the sulfur in the bottom of the combustion chamber. However, while it is thus desirable in many cases,

as for making nitrogen on a very large scale,

to'heat the air before supplying it to the sulfur, Iam enabled to carry out my process by burning the sulfur with air no. heated before being introduced into the combustion chamber,- this air being supplied through the charging opening 2, the cover 3 being then removed.

In order to successfully practise this invention, two main conditions are necessary. First, the furnace must be so constructed that the air of combustion is compelled, before escaping from the combustion cham fur, which, near the point of exit, would be in a molten condition with sulfur vapors arising therefrom; and, secondly, the sulfur must be in excess,-o rat any rate no more air must be supplied to the sulfur than is the oxygen for combustion thereof.

As willhere'inafter ap'pear,the gases from the furnace have to pass through a long se ries of purifying chambers, in order to supply any air to the furnace, a suction pump is necessary at the end of said series. Now, for a given rate of feed ing the sulfur, the suction pum must bi. so operated that-the current of a1r supplied thereby is never more than necessary, as above mentioned. So'long as sulfur vapor passes off unconsumed, as eyidenced by the into close proximity to the sul" and, therefore,

formation of sublimed sulfur in the. condensing chambers, the process is being propcarried ut. v

the apparatus itself, that is, the furnace, which is the essential element as within thescope of my invention.

From the outlet 7 of the furnace, the gases pass upward by a pipe 10. Should any oxygen have been unconsumed by the sulfur before reachingthe pipe 10, it will certainly combine with the excess sulfur vapor therein, the pipe 10 being intensely hot; From the pipe 10 the gases, consisting of nitrogen, sulfurous anhydrid, sulfur vapor, and a small amountof steam, due to the presence of moisture in the atmospheric air supplied to the furnace, then pass in succession through two subliming chambers 11, 12, which are suflicient to condense andprecipitate in, the form 'of sublimed sulfur .nearly all the excess of sulfur which has Q passed off in the form of vapor. I

From the top of the second subliming chamber 12, the nitrogen andsulfurous anhydrid pass into the top of asulfurous acid tower 13, in the top of which is arranged a spraying device .14 which sprays water thereinto. In said tower are placed one above the other-alternating trays 18, 19, of two series, the trays 1 8 of one series having a central passage 20, and those of the other having an annular space 21 between the side of the tray and the side of the tower, through which the gases canpass. I The water is compelled to flow from one tray to' the next belowit either through acentral opening 20, or through one of the annular passages 21. This water, if not too much, passing through the nitrogen and sulfurous anhydrid gases, forms from the latter strong sulfurous' acid, which is collected by a pipe 15 from a liquid seal 16 at the bottom of said tower. The nitrogen and part of the sulfurous anhydrid gases then pass into the bottom of a second tower 17, into the top of which water is also sprayed, the amount of water supplied in this tower being greater than that in the first tower, so that'sulffirous acid in much larger quantity, but greatly diluted, is col-, l'oted therefrom. 7

From the tower 17 the gases pass through perforations 22 of a supply pipe 23 entering the bottom of a wash vessel 24 and pass upward between pieces of some porous sub' stance 25, such as coke, which exposes a eat extent-of surface, upon which water is sprayed by means of a sprayer 26, so that the sulfurous anhydrid .gas coming in contact with the m'oist'*surface forms with the water diluted sulfurous acid, which is collected at the bottom in the same manneras before,. a

Fronr the top of thewa'sh vessel 24 the gases pass through a, perforated pipe '30 into the bottom of a wash vessel 31, about half filled with a solution 32 of caustic potash, which serves to effectually arrest any trace of sulfurousacid or carbonic acid.

gas, and forming sulfit'e of potassium, which is valuable in the arts. From the top ofthe vessel 31 the gases pass into avess'el 33.

which is'about half filled with calcium chlorid 34 to take'up the moisture. This vessel .is used when dry nitrogen is required for use as a preservative, but in other cases,

' when the nitrogen is not so used, the calcium chlorid may be omitted. From the top of the latter vessel thegas passes to a suction pump 35, which creates thecurrent which draws the air into the furnace and the gases through the series of chambers, and which likewise forces the nitrogen gas into a suit-v able receiver 36, from which it may be drawn out as required for use.

,By using a suction pump to draw the gases through the furnace I- insure that the products of combustion shall have a greater velocity than, or a velocity at least as great as, the air that flows into their place. From this it results that the sulfurous fumes are carried off as quickly as formed, and the air can have free access to the surface of the burning sulfur.

, In order to economize in respect of the chemical reagents in the vessels 31, 33, there is provided a bypass pipe 37, having a valve 38, which is opened in commencing the process, and is closed as soon as the gas is sufiiciently free from o of the pump is a discharge pipe 39 having.

gen. On the. other side a valve 40 therein. A valve 41 is interposed 1 between the vessels 24 and 31, anda valve 42 between the suction pump and the receiver.

The valves 38 and 40 are openedand the valves 41 and 42 are closed on commencing the process, and the gas emerging through the pipe 39 --is tested until it is foundto be 'sutficiently free from oxygen,

and then said valves are closed and the valves 41, 42, are opened, and the gas is passed intothe receiver 36. i

It will be understood that in all cases the vessels are composedof suitable material, suchas earthenware, or, in certain cases, of

7 iron lined with lead, to withstand the action of the; acids passing therethrough." It is also important that said vessels are made perfectly air-tight.

. I have found that by the above process nitrogen-of great purity can be obtained from the atmosphere. In practising this process, it has'been-my custom to reject all nitrogen gas which does not reach a purity of 99.6 to 99.8 percent. 'Generally speaking,

it isonly retained at the latter degree of purity. By placing iron filingsin the re- Iceiver fora few days, even th1s small percentage of oxygen, '2 per cent, is found to by processes heretofore'attempted cominerbe absent, and the receiver then contains absolutely-pure nitrogen.

The costof obtaining nitrogen byhthe above process is very much less than those cially, so far as my knowledge extends.

I make no claim herein to the apparatusv disclosed in this'application as said apparatus forms the subject of a separate application, Serial No. 544,212, the same being a division of this application, said-app1ica-- tion having matured into Patent No. 993,017.

I claim:' v 1. A continuous process of obtaining substantially pure nitrogen from atmospheric air which consists in causing molten sulfur to flow in a stream, feeding sulfur and supplying air at one end of said stream While restricting the amount of air supplied so that no more oxygen will be present than is suflicient to combine with the sulfunfrom said stream, compelling the whole of the air.

to How, inits whole course, close to the surface of the burning sulfur, conducting away, while confining, the sulfurous acid,

unburned same, and nitrogen, depositing ,theunburned sulfur, washing out the sulfurous acid, and collecting the nitrogen,

substantially as described.

I 2. The process of obtaining substantially pure nitrogen from atmospheric air which consists in directing the whole of a stream of air downward into close proximity to the surface of burning sulfur, restricting the magnitude of said stream so that no more oxygen will'b'e present than sufiices to combine with the sulfur arising therefrom, re-

ducing the height of said stream as it ad- Vances, while Increasing its velocity, con

ducting away the sulfurous acid, unburned sulfur, and nitrogen, and removing therefrom the unburned sulfur and sulfurous acid.

In testimony whereof I have hereunto set my hand in the presence of two subscribing Copies ,0! this patent may be obtained torvfive cents each, by' addressing the Commissioner of Iatents,

Washington, D. G. 

